From: Marc Zyngier <maz@kernel.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: "Richard Henderson" <richard.henderson@linaro.org>,
"Shashi Mallela" <shashi.mallela@linaro.org>,
qemu-arm@nongnu.org, "Alex Bennée" <alex.bennee@linaro.org>,
qemu-devel@nongnu.org
Subject: Re: [PATCH for-6.2? 0/2] arm_gicv3: Fix handling of LPIs in list registers
Date: Mon, 29 Nov 2021 09:19:33 +0000 [thread overview]
Message-ID: <87v90bmi8q.wl-maz@kernel.org> (raw)
In-Reply-To: <20211126163915.1048353-1-peter.maydell@linaro.org>
Hi Peter,
On Fri, 26 Nov 2021 16:39:13 +0000,
Peter Maydell <peter.maydell@linaro.org> wrote:
>
> (Marc: cc'd you on this one in case you're still using QEMU
> to test KVM stuff with, in which case you might have run into
> the bug this is fixing.)
Amusingly enough, I have recently fixed [1] a very similar issue with
the ICV_*_EL1 emulation that KVM uses when dealing with sub-par HW
(ThunderX and M1).
When writing this a very long while ago, I modelled it so that LPIs
wouldn't have an Active state, similar to bare metal. As it turns out,
the pseudocode actually treats LPIs almost like any other interrupt,
and is quite happy to carry an active bit that eventually gets exposed
to the hypervisor.
I don't think this ever caused any issue, but I'd be pretty happy to
see the QEMU implementation fixed.
For the whole series:
Reviewed-by: Marc Zyngier <maz@kernel.org>
Thanks,
M.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm64/kvm/hyp/vgic-v3-sr.c?id=9d449c71bd8f74282e84213c8f0b8328293ab0a7
--
Without deviation from the norm, progress is not possible.
prev parent reply other threads:[~2021-11-29 9:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-26 16:39 [PATCH for-6.2? 0/2] arm_gicv3: Fix handling of LPIs in list registers Peter Maydell
2021-11-26 16:39 ` [PATCH for-6.2? 1/2] hw/intc/arm_gicv3: Add new gicv3_intid_is_special() function Peter Maydell
2021-11-28 16:29 ` Alex Bennée
2021-11-26 16:39 ` [PATCH for-6.2? 2/2] hw/intc/arm_gicv3: fix handling of LPIs in list registers Peter Maydell
2021-11-29 9:19 ` Marc Zyngier [this message]
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